Electroless plating production of nickel and cobalt structures

Abstract

A method comprising forming a structural element 115 on a surface 620 of a layer 510 via an electroless plating of nickel or cobalt 130 onto the surface, the layer being rigidly fixed to an underlying substrate 110 . The method also comprises etching away a portion of the layer such that a part of the structural element is able to move with respect to the substrate.

1 . A method of manufacture, comprising:
 forming a structural element on a surface of a layer via an electroless plating of nickel or cobalt onto said surface, said layer being rigidly fixed to an underlying substrate; and   etching away a portion of said layer such that a part of said structural element is able to move with respect to said substrate.   
     
     
         2 . The method of  claim 1 , further comprising forming a mask on said substrate, forming a window in said mask, and removing a portion of said layer exposed by said window to expose a portion of said substrate's surface. 
     
     
         3 . The method of  claim 2 , wherein said electroless plating of said nickel or cobalt further includes forming a part of said structural element directly onto said exposed portion of said substrate surface. 
     
     
         4 . The method of  claim 1 , further comprising:
 forming a second mask on said surface, said second mask including a second window exposing a part of said surface.   
     
     
         5 . The method of  claim 4 , wherein forming said second mask further includes patterning said second mask such that said second window defines a first beam and a second beam of said structural element, wherein said second beam is parallel to said first beam. 
     
     
         6 . The method of  claim 1 , wherein said structural element includes nickel or cobalt and phosphorous or boron. 
     
     
         7 . The method of  claim 1 , wherein said electroless plating includes contacting said surface with a plating solution containing nickel or cobalt and a reducing-agent. 
     
     
         8 . The method of  claim 7 , wherein said plating solution includes a nickel or cobalt salt and said reducing-agent has hypophosphite anions, such that there is about 9 atomic percent or higher phosphorous content in said structural element. 
     
     
         9 . The method of  claim 7 , wherein said plating solution includes a nickel or cobalt salt and said reducing-agent has sodium borohydride or dimethylaminoborane, such that there is about 9 atomic percent or higher boron content in said structural element. 
     
     
         10 . The method of  claim 1 , wherein a seed layer is deposited on said surface before said electroless plating of nickel. 
     
     
         11 . The method of  claim 1 , wherein etching away said portion of said layer includes removing substantially all of said layer. 
     
     
         12 . The method of  claim 1 , wherein forming said structural element includes forming two parallel beams wherein an end of each of said beams is anchored to said substrate and opposite end of said beams is movable with respect to said substrate. 
     
     
         13 . The method of  claim 1 , further including manufacturing a microelectromechanical thermal actuator device, including:
 electrically coupling a voltage source to said structural element;   forming a second structural element on said substrate, wherein said second structural element is adjacent to said structural element but electrically isolated from said structural element when said structural element is not actuated; and   electrically coupling a transmitter and a receiver to one or both of said structural element or said second structural element.   
     
     
         14 . The method of  claim 1 , wherein said electroless plating forms said layer as a monolayer of nickel or cobalt alloyed with phosphorus or boron and having a substantially amorphous structure, said monolayer being rigidly fixed to said underlying substrate. 
     
     
         15 . The method of  claim 1 , wherein said etching away said portion of said layer, is such that said part of said structural element is separately moveable with respect to said substrate.